Maybe, but keep in mind that single high DPS weapons provide huge bonuses to squads by preventing DPS drop off as members of the squad die, and by causing all DPS to be trained at a single model. Both of these effects need also be considered in the cost, DPS alone is not enough.
Obers are already out of the box elite infantry available to OKW (normally call-in only), with some of the best received accuracy, and the best vet of any elite infantry in the game. Asking that they require a large investment in their MG's requires they be taken care of well and used appropriately.
I am open to changes in cost not equal to 120 munitions (this was more of a guide), but I think it fair based on their performance.
Obers might be non-doctrinal but they also come very late. They need that LMG to have any meaningful impact when they come out so I don't think their LMG needs to be much more expensive at all considering their already high price + pop cap.
75 ammo would be fine.
P.S.: All LMGs focus one model, or am I mistaken?